sound/i2c/i2c.c

   1 /*
   2  *   Generic i2c interface for ALSA
   3  *
   4  *   (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
   5  *   Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; either version 2 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with this program; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  20  *
  21  */
  22
  23 #include <sound/driver.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include <linux/errno.h>
  28 #include <sound/core.h>
  29 #include <sound/i2c.h>
  30
  31 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  32 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
  33 MODULE_LICENSE("GPL");
  34
  35 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
  36                                  unsigned char *bytes, int count);
  37 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
  38                                  unsigned char *bytes, int count);
  39 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
  40                                  unsigned short addr);
  41
  42 static struct snd_i2c_ops snd_i2c_bit_ops = {
  43         .sendbytes = snd_i2c_bit_sendbytes,
  44         .readbytes = snd_i2c_bit_readbytes,
  45         .probeaddr = snd_i2c_bit_probeaddr,
  46 };
  47
  48 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
  49 {
  50         struct snd_i2c_bus *slave;
  51         struct snd_i2c_device *device;
  52
  53         snd_assert(bus != NULL, return -EINVAL);
  54         while (!list_empty(&bus->devices)) {
  55                 device = snd_i2c_device(bus->devices.next);
  56                 snd_i2c_device_free(device);
  57         }
  58         if (bus->master)
  59                 list_del(&bus->buses);
  60         else {
  61                 while (!list_empty(&bus->buses)) {
  62                         slave = snd_i2c_slave_bus(bus->buses.next);
  63                         snd_device_free(bus->card, slave);
  64                 }
  65         }
  66         if (bus->private_free)
  67                 bus->private_free(bus);
  68         kfree(bus);
  69         return 0;
  70 }
  71
  72 static int snd_i2c_bus_dev_free(struct snd_device *device)
  73 {
  74         struct snd_i2c_bus *bus = device->device_data;
  75         return snd_i2c_bus_free(bus);
  76 }
  77
  78 int snd_i2c_bus_create(struct snd_card *card, const char *name,
  79                        struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
  80 {
  81         struct snd_i2c_bus *bus;
  82         int err;
  83         static struct snd_device_ops ops = {
  84                 .dev_free =     snd_i2c_bus_dev_free,
  85         };
  86
  87         *ri2c = NULL;
  88         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
  89         if (bus == NULL)
  90                 return -ENOMEM;
  91         mutex_init(&bus->lock_mutex);
  92         INIT_LIST_HEAD(&bus->devices);
  93         INIT_LIST_HEAD(&bus->buses);
  94         bus->card = card;
  95         bus->ops = &snd_i2c_bit_ops;
  96         if (master) {
  97                 list_add_tail(&bus->buses, &master->buses);
  98                 bus->master = master;
  99         }
 100         strlcpy(bus->name, name, sizeof(bus->name));
 101         if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
 102                 snd_i2c_bus_free(bus);
 103                 return err;
 104         }
 105         *ri2c = bus;
 106         return 0;
 107 }
 108
 109 EXPORT_SYMBOL(snd_i2c_bus_create);
 110
 111 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
 112                           unsigned char addr, struct snd_i2c_device **rdevice)
 113 {
 114         struct snd_i2c_device *device;
 115
 116         *rdevice = NULL;
 117         snd_assert(bus != NULL, return -EINVAL);
 118         device = kzalloc(sizeof(*device), GFP_KERNEL);
 119         if (device == NULL)
 120                 return -ENOMEM;
 121         device->addr = addr;
 122         strlcpy(device->name, name, sizeof(device->name));
 123         list_add_tail(&device->list, &bus->devices);
 124         device->bus = bus;
 125         *rdevice = device;
 126         return 0;
 127 }
 128
 129 EXPORT_SYMBOL(snd_i2c_device_create);
 130
 131 int snd_i2c_device_free(struct snd_i2c_device *device)
 132 {
 133         if (device->bus)
 134                 list_del(&device->list);
 135         if (device->private_free)
 136                 device->private_free(device);
 137         kfree(device);
 138         return 0;
 139 }
 140
 141 EXPORT_SYMBOL(snd_i2c_device_free);
 142
 143 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 144 {
 145         return device->bus->ops->sendbytes(device, bytes, count);
 146 }
 147
 148 EXPORT_SYMBOL(snd_i2c_sendbytes);
 149
 150 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 151 {
 152         return device->bus->ops->readbytes(device, bytes, count);
 153 }
 154
 155 EXPORT_SYMBOL(snd_i2c_readbytes);
 156
 157 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 158 {
 159         return bus->ops->probeaddr(bus, addr);
 160 }
 161
 162 EXPORT_SYMBOL(snd_i2c_probeaddr);
 163
 164 /*
 165  *  bit-operations
 166  */
 167
 168 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
 169 {
 170         if (bus->hw_ops.bit->start)
 171                 bus->hw_ops.bit->start(bus);
 172 }
 173
 174 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
 175 {
 176         if (bus->hw_ops.bit->stop)
 177                 bus->hw_ops.bit->stop(bus);
 178 }
 179
 180 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
 181 {
 182         if (bus->hw_ops.bit->direction)
 183                 bus->hw_ops.bit->direction(bus, clock, data);
 184 }
 185
 186 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
 187 {
 188         bus->hw_ops.bit->setlines(bus, clock, data);
 189 }
 190
 191 #if 0
 192 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
 193 {
 194         if (bus->hw_ops.bit->getclock)
 195                 return bus->hw_ops.bit->getclock(bus);
 196         return -ENXIO;
 197 }
 198 #endif
 199
 200 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
 201 {
 202         return bus->hw_ops.bit->getdata(bus, ack);
 203 }
 204
 205 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
 206 {
 207         snd_i2c_bit_hw_start(bus);
 208         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 209         snd_i2c_bit_set(bus, 1, 1);
 210         snd_i2c_bit_set(bus, 1, 0);
 211         snd_i2c_bit_set(bus, 0, 0);
 212 }
 213
 214 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
 215 {
 216         snd_i2c_bit_set(bus, 0, 0);
 217         snd_i2c_bit_set(bus, 1, 0);
 218         snd_i2c_bit_set(bus, 1, 1);
 219         snd_i2c_bit_hw_stop(bus);
 220 }
 221
 222 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
 223 {
 224         snd_i2c_bit_set(bus, 0, data);
 225         snd_i2c_bit_set(bus, 1, data);
 226         snd_i2c_bit_set(bus, 0, data);
 227 }
 228
 229 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
 230 {
 231         int ack;
 232
 233         snd_i2c_bit_set(bus, 0, 1);
 234         snd_i2c_bit_set(bus, 1, 1);
 235         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 236         ack = snd_i2c_bit_data(bus, 1);
 237         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 238         snd_i2c_bit_set(bus, 0, 1);
 239         return ack ? -EIO : 0;
 240 }
 241
 242 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
 243 {
 244         int i, err;
 245
 246         for (i = 7; i >= 0; i--)
 247                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
 248         if ((err = snd_i2c_bit_ack(bus)) < 0)
 249                 return err;
 250         return 0;
 251 }
 252
 253 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
 254 {
 255         int i;
 256         unsigned char data = 0;
 257
 258         snd_i2c_bit_set(bus, 0, 1);
 259         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 260         for (i = 7; i >= 0; i--) {
 261                 snd_i2c_bit_set(bus, 1, 1);
 262                 if (snd_i2c_bit_data(bus, 0))
 263                         data |= (1 << i);
 264                 snd_i2c_bit_set(bus, 0, 1);
 265         }
 266         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 267         snd_i2c_bit_send(bus, !!last);
 268         return data;
 269 }
 270
 271 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
 272                                  unsigned char *bytes, int count)
 273 {
 274         struct snd_i2c_bus *bus = device->bus;
 275         int err, res = 0;
 276
 277         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 278                 return -EIO;            /* not yet implemented */
 279         snd_i2c_bit_start(bus);
 280         if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
 281                 snd_i2c_bit_hw_stop(bus);
 282                 return err;
 283         }
 284         while (count-- > 0) {
 285                 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
 286                         snd_i2c_bit_hw_stop(bus);
 287                         return err;
 288                 }
 289                 res++;
 290         }
 291         snd_i2c_bit_stop(bus);
 292         return res;
 293 }
 294
 295 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
 296                                  unsigned char *bytes, int count)
 297 {
 298         struct snd_i2c_bus *bus = device->bus;
 299         int err, res = 0;
 300
 301         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 302                 return -EIO;            /* not yet implemented */
 303         snd_i2c_bit_start(bus);
 304         if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
 305                 snd_i2c_bit_hw_stop(bus);
 306                 return err;
 307         }
 308         while (count-- > 0) {
 309                 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
 310                         snd_i2c_bit_hw_stop(bus);
 311                         return err;
 312                 }
 313                 *bytes++ = (unsigned char)err;
 314                 res++;
 315         }
 316         snd_i2c_bit_stop(bus);
 317         return res;
 318 }
 319
 320 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 321 {
 322         int err;
 323
 324         if (addr & 0x8000)      /* 10-bit address */
 325                 return -EIO;    /* not yet implemented */
 326         if (addr & 0x7f80)      /* invalid address */
 327                 return -EINVAL;
 328         snd_i2c_bit_start(bus);
 329         err = snd_i2c_bit_sendbyte(bus, addr << 1);
 330         snd_i2c_bit_stop(bus);
 331         return err;
 332 }
 333
 334
 335 static int __init alsa_i2c_init(void)
 336 {
 337         return 0;
 338 }
 339
 340 static void __exit alsa_i2c_exit(void)
 341 {
 342 }
 343
 344 module_init(alsa_i2c_init)
 345 module_exit(alsa_i2c_exit)